1. Field of the Invention
This invention pertains to the beverage filling art and more particularly relates to a system for directing an inert gas into a container during the filling operation to purge substantially all of the air from the container and prevent the contamination of the beverage.
2. Description of the Prior Art
The desirability of removing air from filled containers and then filling the headspace with an inert gas prior to sealing to prevent oxidation of the product in the container is well known in the art. In my U.S. Pat. Nos. 3,236,023 and 3,443,352 methods are disclosed wherein product filled containers are placed in vacuum chambers so that air can be evacuated from the chamber and the headspace of the containers. An inert gas is thereafter directed into the vacuum chamber and headspace of the container, and the container is subsequently released from the chamber and sealed.
However, certain products, such as carbonated beverages, cannot be purged of air by vacuumization without a great loss of dissolved carbon dioxide in the beverage and, accordingly, a substantial reduction in quality.
Fillers for carbonated beverages, such as beer and soft drinks, are well known in the art, and the containers are usually filled while the containers are under a superatmospheric pressure of about 15-40 psi gauge. When filling carbonated beverages under superatmospheric pressure, the air within the container is usually discharged through a passage in the filling valve and into the superatmospheric headspace in the supply tank resulting in an undesirable mixture of air and carbon dioxide in the headspace of the tank. Also, pressure fillers of the above type were provided with snifter valves to bleed headspace air and carbon dioxide from the container headspace before the container was opened to the atmosphere.
My recently issued U.S. Pat. No. 3,779,292 discloses a beverage filling apparatus wherein a measuring cylinder having a filling valve at the lower end thereof is inserted into the container to be filled. When the measuring cylinder reaches near the bottom of the container, the volume of the cylinder is mechanically expanded slightly to reduce the pressure on the beverage, and then the filling valve is opened and the cylinder is moved upwardly relative to the container to allow the measured quantity of beverage in the cylinder to flow into the container.
When filling with a bottom opening filler of the type disclosed in the aforementioned U.S. Pat. No. 3,779,292, introduction of the filling cylinder into the open container displaces most of the air therefrom, and the subsequent opening of the cylinder and release of the beverage therein displaces the rest of the air therefrom to provide a beverage of high quality. However, it is recognized that small quantities of air remain in the container during the filling operation and come into contact with the beverage as it is being filled into the containers. It has also been recognized that such small quantities of air may become absorbed or entrained in the beverage itself so as to contaminate it.